In the prior art, in the semiconductor packages using the lead frames, there is the semiconductor package having a structure in which the semiconductor element is mounted on the die pad, and the semiconductor element and a plurality of leads are connected via a wire respectively, and both surfaces of the die pad, the semiconductor element, and respective wires are sealed with a sealing resin.
In such semiconductor package, in order to improve adhesion of the sealing resin on the backside of the die pad, a large number of dimples are provided on the backside of the die pad. The dimples provided on the backside of the die pad are formed in a shape such as a quadrangular pyramid, or the like by the stamping. Consequently, adhesion of the sealing resin on the backside of the die pad is not always sufficient.
A related art is disclosed in Japanese Laid-open Patent Publication No. 07-161896, Japanese Laid-open Patent Publication No. 07-273270, and Japanese Laid-open Patent Publication No. 2009-260282.